Publication: GAS6 (growth arrest speciıfic 6) / tam reseptör yolağının kronik lenfositik lösemiyle ilişkisi
Abstract
TYRO3, AXL ve MER, TAM Reseptör ailesinin fertleridir. “Growth Arrest Specific 6”, Gas6, bu onların ligandıdır. Solid kanserlerde, Axl reseptörünün arttığı gösterilmiştir. Kronik lenfositer lösemi (KLL), kemik iliği ve kanda B Hücrelerin kontrolsüz gelişimi ve lenfositozla karakterize hematolojik bir malinetedir. Kanser hücreleriyle stromal komponentler arasındaki ilişkinin moleküler mekanizması henüz aydınlatılamamıştır. KLL ile TAM reseptör ilişkisi tarandığında, TYRO3 ile ilgili hiçbir çalışmaya rastlanmamıştır. Bu tezin amacı, başta TYRO3 olmak üzere TAM reseptörlerinin kandaki değişimini KLL (B-Hücre)de araştırmaktır. Bu çalışmaya, ilaç kullanmaya başlamamış 35 KLL hastası alındı (47-79 yaş aralığında; yaş ortalaması 63,25±10,94; 18 erkek ve 17 kadın; Rai Sınıflandırılması Evre: 0, I, II). Kontrol Grubuna 31 sağlıklı gönüllüden oluşuyordu (51-76 yaş aralığında; yaş ortalaması 62,24±7,78; 21 erkek ve 10 kadın). EDTA’lı tüplere kan örnekleri alındı. Lenfositlerin yüzeyindeki üç farklı TAM reseptörü, akım sitometrik yöntemle ölçüldü. Kan hücrelerinde (eritrosit içermeyen), bu reseptörleri kodlayan mRNAlar, Gerçek Zamanlı Polimeraz Zincir Reaksiyonuyla (PZR) ölçüldü. Ayrıca, plazma GAS6 seviyeleri ELISA (R&D) ile ölçülerek diğer bulgularla karşılaştırıldı. Akım sitometri deneyleri sonucunda, KLL grubunda lenfosit yüzeyindeki AXL, TYRO3 ve MER reseptörlerinin üçü de kontrol grubuna göre anlamlı olarak yüksek bulundu (p<0,05). Plazma GAS6 seviyeleri, kontrole göre daha düşüktü (p< 0.01). Median (25. Persantil – 75. Persantil) olarak plazma GAS6 seviyesi (ng/ ml): KLL grubunda 1,19 (0,59-1,8) ve kontrol grubunda 5,7 (2,7-7,8) olarak ölçüldü. Gerçek zamanlı PZR sonuçlarına göre, TYRO3 ve AXL için mRNA seviyeleri kontrolden anlamlı olarak yüksek bulundu (p< 0.05); ancak MER ve GAS6 kontrolden farklı değildi (p> 0.05). Plazma GAS6 ölçümüyle literatürde ilk bulgular elde edildi. Plazma GAS6, KLL hastalarının takibinde yeni bir bio-belirteç olabilir. Yine ilk defa KLL’de hem mRNA hem de protein olarak Tyro3 lenfositlerde yüksek bulundu. İleri araştırmalar bu bulguların klinik önemini ve GAS6/ TAM yolağı ile B-Hücre-KLL ilişkisini ortaya çıkaracaktır. TAM reseptörleri, GAS6, Kronik Lenfositer Lösemi .
Relationship between Growth Arrest Specific 6/ TAM signaling and Chronic Lymphocytic Leukemia Axl, Tyro3 and Mer belong to the TAM Receptor family. “Growth Arrest Specific 6”, GAS6, is a ligand for TAM receptors. Over expression of Axl has been shown in some types of solid cancers. Chronic Lymphocytic Leukemia (CLL) is a hematological malignancy, characterized with uncontrolled proliferation of B-lymphocytes in the blood and bone marrow. Molecular mechanism between cancer cells and stromal components has not been enlightened in hematological malignancies. The objective of this thesis is to search the relationship between B-Cell-CLL and TAM receptors in the blood. 35 B-Cell-CLL patients (grade 0-II, according to the classification of Rai), who were not on a drug treatment, were recruited in this study (17 female, 18 male). Their ages were 47 to 79 years (63,25±10,94), and the control group consisted of 31 healthy volunteers (10 female, 21 male), whose age range was 51-76 years (62,24±7,78). TAM receptors expressing on the surface of lymphocytes were measured by flow cytometry using appropriate antibodies against TAM receptors. mRNAs of TAM receptors in the blood cells (except erythrocytes)was detected by Real Time - Polymerized Chain reaction (PCR). Additionally, plasma GAS6 levels were measured by ELISA (R&D). In the CLL group, three type of TAM receptors on the surface of lymphocytes were higher than those of the control group (p<0,05). Plasma GAS6 levels were significantly lower than those of the control group [Median (25. Percentile– 75. Percentile)] (ng/ ml): 1,19 (0,59-1,8) for CLL and 5,7 (2,7-7,8) for the control group (p< 0,01). Real Time – PCR results in comparison with the control, indicated that expression of TYRO3, first time in CLL with this study, was higher significantly in CLL (p< 0.05), as well as AXL, whereas there were no difference for MER and GAS6 (p> 0.05). Plasma GAS6, first results obtained in CLL with this study, may be a bio-marker for monitoring CLL patients. Further studies focusing on molecular mechanisms are required to elucidate the actual role of GAS6/ TAM signaling in B-Cell-CLL. The results of this thesis may stimulate new areas of research and offer potential therapeutic interventions. Key Words: TAM receptors, GAS6, Chronic Lymphocytic Leukemia (CLL
Relationship between Growth Arrest Specific 6/ TAM signaling and Chronic Lymphocytic Leukemia Axl, Tyro3 and Mer belong to the TAM Receptor family. “Growth Arrest Specific 6”, GAS6, is a ligand for TAM receptors. Over expression of Axl has been shown in some types of solid cancers. Chronic Lymphocytic Leukemia (CLL) is a hematological malignancy, characterized with uncontrolled proliferation of B-lymphocytes in the blood and bone marrow. Molecular mechanism between cancer cells and stromal components has not been enlightened in hematological malignancies. The objective of this thesis is to search the relationship between B-Cell-CLL and TAM receptors in the blood. 35 B-Cell-CLL patients (grade 0-II, according to the classification of Rai), who were not on a drug treatment, were recruited in this study (17 female, 18 male). Their ages were 47 to 79 years (63,25±10,94), and the control group consisted of 31 healthy volunteers (10 female, 21 male), whose age range was 51-76 years (62,24±7,78). TAM receptors expressing on the surface of lymphocytes were measured by flow cytometry using appropriate antibodies against TAM receptors. mRNAs of TAM receptors in the blood cells (except erythrocytes)was detected by Real Time - Polymerized Chain reaction (PCR). Additionally, plasma GAS6 levels were measured by ELISA (R&D). In the CLL group, three type of TAM receptors on the surface of lymphocytes were higher than those of the control group (p<0,05). Plasma GAS6 levels were significantly lower than those of the control group [Median (25. Percentile– 75. Percentile)] (ng/ ml): 1,19 (0,59-1,8) for CLL and 5,7 (2,7-7,8) for the control group (p< 0,01). Real Time – PCR results in comparison with the control, indicated that expression of TYRO3, first time in CLL with this study, was higher significantly in CLL (p< 0.05), as well as AXL, whereas there were no difference for MER and GAS6 (p> 0.05). Plasma GAS6, first results obtained in CLL with this study, may be a bio-marker for monitoring CLL patients. Further studies focusing on molecular mechanisms are required to elucidate the actual role of GAS6/ TAM signaling in B-Cell-CLL. The results of this thesis may stimulate new areas of research and offer potential therapeutic interventions. Key Words: TAM receptors, GAS6, Chronic Lymphocytic Leukemia (CLL